The class III phosphatidylinositol-3-kinase (PI3K) known as Vps34 (vacuolar protein sorting 34, encoded by PIK3C3) regulate intracellular membrane trafficking in endocytic sorting, cytokinesis and autophagy. Vps34 forms complexes with other proteins: Vps15 (encoded by PIK3R4, known as p150 in mammalian cells), Vps30 (encoded by VPS30/ATG6 in yeast, equivalent to mammalian Beclin 1, encoded by BECN1) and either Vps38 (UVRAG) or Atg14 (ATG14L). This family includes members such as Vps38 found in Saccharomyces cerevisiae Swiss:Q05919. Vps38 is characteristic of complex II and essential for vacuolar protein sorting. In mammalian cells, complex II is also involved in autophagy, receptor degradation and cytokinesis as well as signaling, recycling and lysosomal tubulation. Independently from complex I and II, Beclin 1 and UVRAG also play separate roles in endosome function and neuron viability. In complex I, Vps38/UVRAG is substituted with Atg14/ATG14L. Although the N-terminal domains of Vps30, Vps38 and Atg14 differ, the overall similarity of their domain organizations suggests that these proteins may have evolved from a common ancestor [1].

1: Structure and flexibility of the endosomal Vps34 complex reveals the basis of its function on membranes. Rostislavleva K, Soler N, Ohashi Y, Zhang L, Pardon E, Burke JE, Masson GR, Johnson C, Steyaert J, Ktistakis NT, Williams RL; Science. 2015;350:aac7365. PMID:26450213